Core drill



Jam 5, 1937.

J. H. HOWARD El' AL v CORE DRILL Filed Feb.v19, 1935 Patented Jan.` 5, `1937 UNITED s'rli'rlzze: PATENT o-FFICE eaerirtsatrms-aslfr signor to Globe Oil Tools Company, LosNic'toil,

Calif., a `corporation of California application February-19.1935, serial No. 'mos `The invention relates to a well drilling tool and relates more particularly to a well core drill.

A general object of this invention is to provide sf claims. '(ci. assvai 4 in longitudinal cross section, and Flg. 7 isjan lenflarged side elevation of the dummy for `replacing the dog type catcher showing 'a portion in vertical cross section.

l The core drill of this invention includes, generally, a tubular body Il, a cutting head Il on the lower end of the body I0, a core catching unit I2 in the head II and a core catching unit I3 in the to recover cores of any character of earth forma'- tion that may be encountered in the drilling of wells'. The drill of the present invention is operable to recover cores of very hard earth formation, cores of' soft earth .formation, undersized cores and broken or shattered cores.

Another object of the invention is 'to provide a core drill that includes a slip type corecatcher operable to break hard solid cores free from the formationand to retain such cores, and a pivoted dog type catcher operable to recover and retain soit cores, undersized cores and broken cores whereby the drill is operable to recover all classes o'f cores. Another object of the invention is to provide a vcore drill of the character mentioned in which thel provisionof the two core catching units does not make the drill bulky or materially complicate its construction. Y

vA iurther object of the invention is to provide a core drill of the character mentioned that includes tubular dummies adapted to occupy the spaces normally occupied by the co're catchers whereby the drill may be operated using only one core catcher without danger of the core fouling th'e shoulder in the upper end ofthe space intended for the core catcher that-is not* in use.

. The various objects and features of our invention will be. fully understood from vthe following -mdleatea by une 2--2 onrlg. a. Fig. 3 is a side side elevation of th'e slip type core catcher showc .ing a portion in vertical cross section.- Fig. 5 is.

. detailed description of a typical preferredv form and application of our invention, throughout which description reference is made to the accompanying drawing, in which: Y

Fig. 1 is a central longitudinalvdetailed sectional view ofthe principal lower end portion of the drill provided by this invention in operation in a well bore. Flg..2 is anv enlarged top vor plan view ofthe dog type core catcher with a portion in transverse cross section, being a view taken as elevation of the dog type catcher witha portion in vertical cross section. Fig. 4 is an enlarged a bottom end view oi the slip type core catcher; Fig. 6 is an enlargedside elevation of the dummy for replacing the slip type catcher with a portion end of the pin I5.

In the type of drill illustrated the body I comprises the outer barrel and is adapted to be connectedwith the operating string or drilling string.' Ill may be madeup of as many tubular' The body parts or sections as required. The lportion of the body III illustrated in -the drawing includes a connecting member or sub Il having a threaded -pin I5 on its lower end.` A tubular member or sub I6 is threaded on the pin I5 to constitutethe lower end member of the body I0. A threaded pin Ilis provided on thelower en'd of thesub I6 for carrying the cuttinghead II. An inner barrel IB is provided'for receiving the core C. 'I'he inner barrel I8 isa thin walled tubular member having a thickened collar L9 welded on its lower end. 'I'he collar I9 is rotatable in the sub I6 to rotatably support and guide the lower end of the f inner barrel I8.V The upper portion o f the longitudinal opening 2'I extending through the sub I6 is enlarged and its lower wall forms an 'upwardly facing annular shoulder 22. The collar AI!) is received in the enlargementy 20 oi the sub openingv 2| and its lower end is adapted to coop- 'erate'with or rest on the shoulder 22. 'I 'hecollar I9 continues upwardly int'o the pin I5 and car'- ries a hardened hearing 23 for cooperating with f the lower end of the pin I5. During drilling when the core C engagesthe interior wall of the inner barrel Il and tends to hold the inner barrel sta` nication with the recess 25. Spaced longitudinal portsv 21- are provided in the wall of the sub I6 and lextend downwardly from the recess. 25 to carry the circulation fluid to the cutting head II.

- 'I'he cutting head Il includes a tubular body or shoe 2 8. .'lhe, shoe 2l hasa threaded vsocket 29 `in its upper end receiving the pin I1. The upper end oi the shoe 28 may be flat to bear against the lower endof the sub` i6. 'I'he socket continues 'downwardly'below the lower end ot the pin l1 lo soV that the lower end of the pin forms a downwardly facing annular shoulder 88. The open lower portion of the socket 28 is plain or unthreaded.' The longitudinal or vertical opening 8I in the shoe 28 Y receives the core C as it is formed and is concentric with the inner barrel I8 so that the coreV is adapted to project upwardly into the inner barrel.

The shoe 28 carries cutting parts or cutting means for making an annular cut in the earth formation and for forming the core 4C. In the particular case illustrated 'the cutting means includes roller cutters A and B. The cutters A and B are rotatably mounted in recesses 82 in the lower end of the shoe 28. Pins 88 extend through the recesses 82 and carry bushings 84 and bearings .85 for rotatably supporting the cutters A and B. 'I'he cutters A which are the inner cutters are substantially cylindrical and project downwardly and inwardly from the recesses 82 to cut the. inner portion of the bore and trim the core C. The cutters A are rotatable about axes inclined downwardly and outwardly relative -to the longitudinal axis of the drill. The outer cutters B aresubstantially frusto-conical and are rotatable about downwardly and inwardly inclined axes. The cutters B project from the, lower end of the shoe 28 and beyond the periphery of the shoe to cut the bore to size. An annular groove 86 isprovided in theupper end of the shoe 28 to .communicate with the lower ends of the ports 21. Ports 81 are provided in the wall of the shoe 28 and extend I downwardly from the groove 88 to the recesses 82 88.`is stepped or of two diameters. Registering annular grooves are provided in the opposing surfaces of the ring sections 88 to form an annular .groove or opening 48. Circumferentially spaced openings 4I are provided in the wall of the ring 88 to intersect the opening 48. The openings 4I have extensions or -conti'nuations 42 extending upwardly in the inner side of the ring toits upper end. The ring 88 is proportioned to be freely i rotatable in the socket 28 so that it is free to oat and remain stationary when the drill is rotating during the drilling operation. The ring, 88 alsol has limited longitudinalmovement in the socket 28.

The core recovering unit I2 includes core engaging and gripping members in the form of piv oted dogs 48 and 44. The dogs 48 and 44 are pivotally supported in theopenings 4I to project from the inner side of the ring 88. Pivot pins 45 extend through transverse openings Vin the dogs I -48 and 44 and the opposite end portions of the pins are received in 'the opening 48. 'I'he pins 45 support the dogs 48 and 44 for pivotal movement between upright inactive positions in the openings 42 and. projecting substantially horizontal positions such as illustrated 'in Figs. 1, 2 and 3 of the drawing. The projecting end portions of the pins 45- are flat or faced on to engage the I The outer section 88 surrounds the upper portion of the. inner'section 88 so that the exterior of the ring wall of the opening 48 for the purpose of holding the pins against rotation and longitudinal movement. .The inward or downward pivoting of the dogs 48 and 44 is' limited by the lower faces of the dogs cooperatingwith the bottom walls of the openings 4I. 'I'he upper and lower faces-of the dogs 48 and 44 converge outwardly to comparatively sharp edges for biting into the core C.

. In accordance with the invention the dogs 48 are comparatively long to project a substantial distance into the interior of the ring 88 when fully actuated. The dogs 44 may be comparatively short. There may be any desired number of core recovering dogs 48 and 4'4. .In the particular case illustrated there are four circumferentially spaced dogs 48 and.i'our dogs 44 spaced between the dogs 48. The spaced long dogs 48 are effective in recovering and retaining soft cores, undersized cores and shattered cores. The shorter dogs 44 are eiective in recovering and retaining mediumhard cores, medium soft cores and full sized core-s. Spring means are provided for urging the dogs 48 and 44 into cooperation with the cre C. Cuts or slots 48 are provided inthe -pivoted end portions of the dogs 48 and 44 and torsional springs 41 are arranged in the slots 46 to surround the pivot pins45. The springs 41 each have an end acting against the ring 88 and an end acting against a dog so that the springs urge the dogs downwardly and inwardly to 'engage Athe core.

The invention includes cam means for positively pivoting the dogs 48'and 44 inwardly to cooperate with the core C when the Ydrill is raised to recover the core.v A downwardly inclined cam shoulder 48 is provided on the wall of the socket .28. The projecting outer ends of the dogs 43 and 44 are provided with cam faces 48 for cooperating with the shoulder 48. When the drill is vraised to recover vthe core C the engagement of the spring urged dogs 48 and- 44 tends to hold the ring 88 against movement so that'the shoulder 48 is moved upwardly into camming engagement with the cam faces 48. This cooperation of the shoulder y 48 with the faces 48 pivots the active ends of the dogs 48 and 44 downwardly and inwardly s o that vthe dogs bite into the core. When the .dogs 43 and 44 are in their fully actuated position they are effectively supported by the lower walls of the openings 4Ito dependably. retain and support the core C.

The core catching unit I8 is effective in breaking free hard cores from the formation and is effective in retaining hard cores. The unit I8 is arranged in the opening 2I at a point spaced above the unit I2. The core catching unit I8 includes a body member 58 movable along the wall of the opening 2|., The lower portion ofA the collar I8 is internally recessed so that its opening forms a continuation of the opening 2I and the collar I8 has an internal downwardly facing shoulder. 5I for limiting the upward movement of the c ore catcher body 58. The lowerportion of the open-- ing 2| has a downwardly and .inwardly inclinedl ring 55, flexible members 54 and the body 58 to attach the flexible members to the body. Core gripping slips 51 are attached to the lower ends ot required inward'flexing of the members 54 and prevent sandfrom accumulating between the flexible members and body 50.

The end portions of the flexible members 54.

projecting upwardly from the core catcher body I! are curved or bent inwardly to engage the core C. The projecting upper end portionsof the exible members 54 are each bifurcated or longitudinally split into two branches or arms 58. v The upper ends of the arms 58 are pointed to bite into the core. The projecting upper ends of the flexy ible members 54 in being longitudinally split are more ilexible so that they do not injure the -core during the drilling operatiorn The vengagement of the projecting upper-:rends of the exible'members 54 with the coreC tends to hold the care catcher I3 against movement and when the drill is raised to recover the core of the core catcher I3 tends to remain stationary so that the inclined e general configuration as the ring 38. When positioned in the open lower end of the socket 28v the dummy E0 prevents the upper end of the core from fouling or striking the shoulder '30. A dummy 5I isy provided to replace the upper core catching unit I3 when the tool is to be operated without the unit I3. The dummy 5I is a tubular member having its lower external surface inclined to seat on the tapered wall 52. When the dummy 6I is in position in the opening 2l it centrally guides the core C and prevents the upper end of the core from engaging the shoulder 5I.

The drill is operated in the well bore in the usual manner so that the cutters A and B make an annular cut in the earth formation and form the coreC. The core `C is received by the openv ing 3 I and passes through the opening 2l into the inner barrel I8.` When the drill is rotating dur.- ing -drilling the dogs 43 and 44 may engage the core to hold the ring 38 against turning and to hold the ring against the shoulder 30. The upper projecting ends of the flexible members 54 contact the core C during drilling to hold the core catcher body 58 against movement and in an up .position where its upper end engages the shoulder 5I. After a core of suiiicient length has been formed the drill is raised to break the core free from the formation. When the drill is raised the spring urged dogs 43 and 44 engage the .core `C to tend to hold the ring 38 against movement so that .the cam shoulder 48 moves upwardly against the cam faces 49 to positively pivot the dogs into the core. The long dogs 43 are adapted to penetrate soft cores and to move under shattered or broken cores. The shorter dogs '44 are adapted to bite into full sized cores and medium hard cores to break them free from the formation. When the dogs 43 and 44 are in their projected or actuated position they are effective in supporting or retaining the core when the drill is being withdrawn from the well.

The upper projecting ends of the flexible members 54 `contact the core to hold `the core catcher body 50 against movement when the drill is raised so that the inclined wall 52 moves against the outerl sides of the slips 51 to force the slips inwardly. The slips 51 are positively actuated to firmly grip hard cores and medium hard'cores.

The gripping engagement of the slips@ 51 with the core is such that the core is 4readily 'broken free might slip through the lowerco're catching""unit l2. The core drill of the present invention having the two core catching units I2 and'IB is operable to recover cores vof. various characters and hard full sized cores asfwell as soft and 4undersized cores. The dummies 60, and 6I 'may be used when the drill is to,be run with only one core catcher. The 50 and 8l are simple, inexpensive'membersjtflit may be readily arranged in the-positions normally occupied by the core catchers-,f :l Y

Having described'only a typical preferred form and application of our invention, we do not wish to be limited orrestricted to the specic detalls set forth, butlwish toreserve to ourselves any changes or variations that may appear to those skilled in the art or fall within the scope of the following claims. i

y Having described our invention, we claim:

1. In a core drill, a tubular body, a cutting head on the lower end ofthe body, a core catcher in the head embodying core engaging dogs, and a core catcher in the body embodying core engaging slips.

2. In a core drill, a tubular body, a cutting head on the lower end of the body, a floating ring in the head, pivoted core engaging dogs on the ring, a floating tubular member in the body above the ring, and core gripping slips carried by the member.

3. In a core drill,` a tubular body, a tubular cutting head on the lower end of the body having an internal recess, a ring rotatable in the recess. pivoted core retaining dogs on the ring, and a core catcher in the body having core gripping slips. Y

4. A core drill, a tubular body having an in,

clined internal surface, a tubular cutting head.

on the lower end of the body having an internal shoulder, a tubular member freelyarranged in the body, core 'gripping slips on the member actuated by cooperation with the said surface, a ring freely arranged in the head and core grip,- plng dogs on the ring actuated by said shoulder.

5. In a core drill,` a tubular body, a tubular cutting head on the lower end of the body having an internal recess, a ring rotatable in the recess. pivoted core retaining dogs on the ring, the dogs being of different lengths, and a core catcher in the body having core gripping slips.

6. A core drill, a tubular body having an inclined internal surface, a tubular cutting head on,

` freely arranged in the head, pivoted core gripping dogs on the ring, and cam -parts on the dogs adapted' to cooperate with the shoulder to actuate the dogs.

7. In a core drill, a cutter head having a socket in its upper end, a tubular body member threaded in the socket so that its lower end forms a shoulder, a ringv shiftable in the socket below the shoulder, pivoted core gripping dogson the ring, a

tubular part shiftable in the body member, and core gripping slips carried by the tubular part LLI eoA

actuated by engagement with the wall of the body member.

8. In a core drill, a tubular body having an inelined internal surface, a tubular cutter head having a socket into which the lower end of the body is threaded, a tubular member shiftable in the body, flexible members on the member having projecting upper ends for engaging the core, slips on the lower ends of the ilexible members actuated to grip the core by cooperating with said surface, a ring shiftable and rotatable in the socket, the lower end of the body limiting the upward movement of the ring, and pivoted core gripping dogs on the ring actuated by relative longitudinal movement between the head and ring.

9. A core drill including a tubular body, an inner barrel rotatably supported at its lower end in the body, the lower end of the inner barrel forming a downwardly facing internal shoulder in the body, a tapered surface on the interior of the body below said shoulder, a member shiftable and rotatable in the body below said shoulder, the shoulder limiting the longitudinal movement of the member, core gripping slips carried by the member and actuated by said surface upon longitudinal movement o1' the body, a cutter head threaded on the body and having an internal recess, the lower end of the body forming the upper wall of the recess, a ring rotatable and shiftable in the recess, and pivoted core gripping dogs on the ring actuated by longitudinal movement of the body.

JOHN H. HOWARD.

ALFRED C. CATLAND. 

